Pump seal and drive construction



July l0, 1945. R. R. cuRTls ETL 2,380,222

PUMP SEAL -AND DRIVE CONSTRUCTION l Filed Feb. l5. 1945 J @if i l i 2lb/mm Patented July 10, 1945 UNITED STATES PATENT oFFlcE 2,380,222 PMP SEAL AND DRIVE CONSTRUCTION Russell R. Curtis and Richard L. Gates, Dayton,

Ohio, assignors to Curtis Pump Company, Dayton, Ohio, a corporation of Ohio Y Application February 15, 1943,' Serial No. 475,930

' (ci. 2st-*11) ,3 Claims.

This invention relates to seal constructions for relatively rotating members whereby the members may be displaced Without affecting the efhciency of the seal.

Speclcally the invention relates to shaft seals of the relatively rotating seal ring type especial- 1y useful in pump constructions and characterized-by maintenance of the same sealing contact between the rings irrespective of axial or transverse displacement of the shaft.

The invention also includes within its scope a drive construction for pumps which cooperates with the seal construction.

While the invention will be hereinafter specically described as embodied in rotary vane type pumps, it should be understood lthat the seals and drive of this invention are useful in many mechanical devices and the invention is not limited to pump installations.

`such as a disk of flexible synthetic plastic material, rubber, synthetic rubber, leather, and the like overlies the recessed face of the rotating seal ring and the shaft ange. A sleeve is pressed on the shaft to clamp the inner marginal portion of the diaphragm tightly against the shaft flange to prevent leakage therebetween. A cup-shaped spring retainer surrounds the rotating seal ring and clamps the outer marginal portion of the diaphragm against the sealing ring to prevent leakage therebetween. A spring acts on the retainer to urge the rotating seal ring against the stationary seal ring.

With this construction the shaft can be cocked or moved axially relative to the seal ring without in any way aifecting the sliding face engagement between the rings since the diaphragm will flex to permit such shaft displacement without displacing the rotating ring.

The shaft itself can be splined into the rotor of a vane-type pump by means of cooperating involute splined teeth on the shaft and pump rotor. The internal pump pressure will act on the splined end of the shaft to force the same away from-the rotor thereby urging the collar-against v parts which is not decreased in efficiency in the event of displacement of the parts.

Sli

a seal construction of the relatively rotating seal ring type which maintains the same sliding face engagement of 4the ring even whenparts carrying the ring are relatively displaced.

A `specific object of the invention is to provide a pump seal including a stationary seal ring, a rotating seal ring driven by the pump shaft, and a flexible diaphragm connecting the shaft and rotating seal ring to permit displacement of the shaft without displacing the ring.

A still further object of the invention is to provide a pump, seal and drive construction wherein pump pressure is eective to urge the pump drive shaft into engagement with a seal ring driven thereby and wherein the pump shaft can be displaced relative to said seal ring without breaking the seal.

Another important object of the invention is to provide a seal construction of the type having relatively rotating rings in sliding .face engagement wherein said engagement is maintained -fby spring pressure applied outwardly of the engaging areas of lthe seal rings.

@ther and further objects of the invention will be apparent to those skilled in the art from the following detailed description of the annexed sheet of drawings which, by way oi preferred examples only, illustrates three embodiments of the invention as applied to rotary vane type Dumps.4

Onthe drawing:

Figure l is a broken vertical cross-sectional view, with parts in elevation, of a rotary vane pump equipped with a seal and drive construction according to this invention.

Figure 2 is a fragmentary cross-sectional view of the seal and drive construction shown in- Figure 1, illustrating the manner in which the pump shaft can be displaced without displacing the seal.

A Figure 3 is a greatly enlarged fragmentary cross-sectional viewillustrating commonly formed ridges and grooves on the seal rings and the manner in which the ridges are always maintained seated in the grooves which they form in accordance with this invention.

Figure 4 is a view similar to Figure 3 illustrating the manner in which the ridges can separate the seal rings in the event that they are Aever displaced from their grooves, thereby breaking sealing contact between the rings.

Figure 5 is a fragmentary vertical cross-sectional view, with parts in elevation, illustrating a modified seal construction wherein the rotating seal ring has a pilot portion seated in the A further object of the invention is to provide Il stationary Seal ring'.

, Figure 6 is a fragmentary cross-sectional view, with parts in elevation, illustrating a different form of spring arrangement for the seal of Figure 1.

As shown on the drawing:

In Figure 1 the reference numeral I0 designates generally a pump including a casing II having pumping means mounted therein including a liner I2 defining, with its inner surface,

ing rings I4 for reduced diameter hub portions I I3a of the rotor. One bearing ring I4 is bottomed on the end wall of the casing IIv and the' other bearing ring I4 is bottomed on the. liner I2. One hub portion I3a extends through and beyond the bearing ring I4 which is bottomed on the liner I2 and is internally splined as at I3b. A spacer sleeve I5 is mounted in the casing II and abuts the outer face of the bearing ring I4 bottomed on the liner I2. the sleeve I5 is beveled as at I5a to provide a recess for a resilient sealing ring or gasket I6.

A stationary seal ring I'I is mounted in `the casing Il and is urged against the gasket ring I6 by the skirt I8a of an end cap I8 for the casing. This end cap is held on an outturned ange IIa of the casing by means of screws such as I 9. The stationary seal ring ,I1 is thus held between the skirt I8a of the ycover and the gasket I6 while the spacer sleeve I5 cooperates to hold the gasket in spaced relation from the bearing ring I4 and thus provides a seal chamber S. C. in the casing.

The cover I8 is centrally apertured as at Ib I and the stationary seal ring I1 is centrally apertured as at IIa.

The stationary seal ring I1 has a raised face` The other end of oping the rotating seal ring 20, which skirt 24a can be spun inwardly on the free .end thereof to fixedly mount the cup on the 'rotating seal ring. 'I'he cup has a wall or base portion 24h overlying the marginal portion of the diaphragm 22 to clamp this marginal portion of the diaf phragm between the cup and the seal ring.

AA collar `or. upstanding flange 24c is also provided on,the cup member to form a retainer for a coil spring 25 held under compression between the base 24224 of the cup and a washer or retainer 2B bottomed on the splined hub Ila of the rotor. 4'Ihe washer 26 is, of course, apertured to receive the splined end 2Ia of the shaft 2I therethrough and. in addition, can have an upstanding fiange or collar 26a around the periphery thereof to center the spring 25. l In the above-described seal construction it will be noted that spring pressure is exerted on the rotating seal ring at the outer peripheral ortion of the ring, which portion is radially utward from the sealing face 20a of the ring. The spring pressure, therefore, tends to always maintain the sealing face in full engagement with the sealing face Ilb of the stationary seal ring l1.

The diaphragm construction is such that no leakage can occur from the sealing chamber S. C.

into the recess 20c of the rotating seal ring be- In the event that the drive shaft is lcocked or wobbled during rotation, as shown in Figure 2.

portion I'Ib projecting into the seal chamber S. C.

and surrounding the aperture Ila for receiving thereagainst the flat face 20a of a rotating seal ring 20. x

The rotating seal ring 20 is centrally apertured as at 20h and has a recessed face opposite the face 20a thereof providing arecess 20c.

A driver or pump shaft -2l extends through the apertures I8b, I'Ia, and 2lb and thence through the `s'eal chamber S. C. to terminate in a splined end portion 2 Ia adapted to slidably seat in the splined hub I3a of the pump rotor. The splined teeth on the hub and on the shaft are arranged in involute form so that the shaft can be dis'- placed in a transverse direction as well as move in an axial direction without disconnecting the drive connection to the rotor.

The shaft 2I-has a second splined-end 2lb outside of the pump adapted f or connection withv an engine drive shaft or other prime mover.

The shaft 2| has a collar portion or flange 2Ic seated in the recess 2Dc of the rotating seal ring 20. This collar 2Ic is of smaller diameter than the recess 20c so as to provide a gap or annular space around the collar. 'I'he ange is bottomed on the bottom of the recess 2lc.

' A exible diaphragm 22 composed` of sheet lmaterial such as'synthetic rubber, synthetic rubthe flange or collar 2Ic thereof may.be moved away from the bottom of the recess 20c of the rotating seal ring 20 but, .in view of the sealed 40 relationship of the diaphragm with the other face of the collar andi-with the sealing ring, leakage from the seal lchamber S. C. cannot occur. Since the rotating seal ringis urged by the spring into full :face engagement with the ber impregnated fabric, synthetic plastic mat'e-l rial, leather, or lthelikie overlies the flange'2lc and the recessed face of the rotating seal ring'- 20. This `diaphragmcan have a bowed' intermediate portion 22a extended into the recess 20c.

A sleeve 23 is pressed onto the shaft 2l 4and has an outturned. flange 22a,l clamping the inner 4 f` stationary seal ring, this rotating seal ring will not cock or tilt with the drive shaft.' The exertion of 'the spring pressure on the rotating seal ring radially outward from both the sealing face 20a of the seal ring and the .collar 2Ic of thedrive shaft will prevent cooking of the seal ring, even though the drive shaft is cocked. Since the diaphragm 22 is clamped, around the inner marginal portion thereof, between the shaft collar 2Ic and the flange 23a of the sleeve 22 which is pressed'tltted onto the shaft andis clamped, around the 'outer .peripheral portion thereof, between the seal ring 2,0 andthe cup 24 spunontothis seal ring, the seal ring 2l is positively driven with the -shaft 2|. l

Theretsiner or.washer 2l.' ofv course, turns with the hub Ila of the rotor driven by the shaft 2| and the spring, between the retainer and cup 24 on the seal ring 20 rotates with the rering 2l isxmetallic, preferably, bei!!! composed in the softer sealing face I1b of the stationary carbon seal ring I1. Now as long as the faces a and I1b are kept in constant engagement, sealing conditions will be maintained since the projections 21 will always ride in the same grooves 28 and separation of the sealing faces 20a and I 1b will not occur. However, as indicated in Figure 4. if either the seal ring I1 or, as is more common, the rotating seal ring 20 becomes temporarily cocked or tilted out of full face engagement with the cooperating ring, the projections 2l willbe movedout of the grooves 2t which they previously formed and will act against the at face i111 thereby separating the face 2da from the face i117 and breaking the seal. Now, even though the projections 21 wear in new grooves in the stationary ring to permit the faces i'ib and ita to again come into full contact, repeated formation of additional grooves will soon open up leakage paths across the sealing face i12 thereby destroying the seal.

If a piece of foreign matter should work in between the faces I'Ib and 20a, it might form grooves in both faces. Repeated movements of the piece of foreign material out of the grooves which it forms would, of course, soon destroy the sealing faces in the same manner as illustrated in Figures 3 and 4i.

In the modication shown in Figure 5, parts identical with parts described in Figures 1 and 2 have been marked with the same reference n umerals. In Figure 5, however, the rotating seal ring 2li has a neck or sleeve portion 20d extending into the aperture Ila of the stationary seal ring preferably in bearing engagement with the aperture-defining wall of the stationary seal ring. This sleeve is integral with the seal ring 2li and serves to prevent any possible cooking of the seal ring so that the sealing face 20a thereof will not leave the face I 1b of the stationary seal ring. The sleeve 20d acts as a pilot portion for centering the stationary seal ring.

In the modification shown in Figure 6, parts identical with parts described in Figures 1 and 2 have also been marked with the same reference numerals. In this modification, however, the

spring retainer 2B is not bottomed on the splined hub 13a of the rotor, but is carried by split washers seated in a groove 2Id of the drive shaft 2i. 'I'hese split washers 30 have flanges 3|la bottoming the retainer 26.

In this arrangement the reaction force of the spring 25 does not tend to force the rotor I3 against the face of the end bearing ring I4 bottomed on the casing II (Figure 1). With the spring retainer 26 bottomed on the shaft 2l as in Figure 6,.and the pump running under pressure, the rotor I3 will operate free of end thrust.

When pump pressure varies on the splined end 2Ia of the drive shaft, the drive shaft will move axially in the splined hub |3a thereby changing the springv pressure on the rotating seal ring 20 in the arrangement of Figure 6. This change in pressure may be' desirable since, when pump pressures are increased, the spring pressure is increased to urge the rotating seal ring against the stationary seal ring with a greater force and thereby tend to increase the seal `eiiiciencyl to resist passage of fluids under higher pressure. At the same time when the pressure decreases, the

spring pressure will decrease. Since the uid will be at lower pressures the high spring pressure is not needed. f

In the modication shown/in Figures 1 and 2 the axial movements of the drive shaft 2| do not affect the spring pressure on the rotating `seal ring since the spring is bottomed on the splined rotor hub I3a.

From the above description it will be understood that this invention provides a very emcient seal for shafts which not only rotate but move axially and transversely without in any way affecting the seal emciency. The seais of this invention include a rotating seal ring in face engagement with a stationary seal ring, resilient means urging the rotating seal ring around the periphery thereof into sealing engagement with the stationary seal ring and a exible diaphragm construction permitting cocking of the drive shaft as well as axial movement thereof without in any way affecting the sliding face engagement hetween the stationary and rotating seal rings.

It will, of course, be understood that various details lof construction may be varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the ap pended claims.

We claim as our invention:

1. A shaft and seal construction comprising a stationary seal ring having a raised face portion providing an annular sealing surface, a rotating seal ring having an annular sealing face for sliding area contact with the face portion. of the stationary seal ring, said rotating seal ring having a recessed face on the side thereofl opposite said annular sealing face, a shaft extending frech7 through both of said rings and having an integral collar in the recess provided by the recessed face ofthe rotating seal ring, said collar being smaller than said recess to provide an annular gap between the periphery of the collar and the rortating seal ring, a non-metallic flexible diation of the diaphragm against the seal ring, and' a spring acting on the base of the cup to urge the annular sealing face of the rotating seal ring `against the raised face of the stationary seal ring.

2. A seal construction comprisingv a pair of apertured seal members, means urging said members into sliding face to face engagement, a shaft extending freely through the apertures of said members, an integral collar on said shaft normall? engaging a face of one of said members, spring means urging said one member against the other member, and a pliable diaphragm in sealing engagement with said one member and said collar and having an unobstructed bowed intermediate portion adapted to be flexed whenever the collar is moved out of engagement with said one member while preventing leakage past the collar.

3. A shaft and seal construction comprising a stationary seal member having a face portion providing an' annular seating surface, a rotating seal 

